GB634534A - Improved process for the synthesis of hydrocarbons - Google Patents

Abstract

The synthesis of hydrocarbons and oxygenated products from carbon monoxide and hydrogen is effected by contacting in a conversion zone with a suspension of finely-divided synthesis catalyst in a gas, the concentration of <PICT:0634534/III/1> catalyst in said suspension being sufficiently low to permit conversion and resultant heat release to take place at a substantially uniform rate over an extended path of contact between reactants and catalyst, unreacted gases being withdrawn and contacted with a dense turbulent fluidized catalyst mass to effect substantial completion of the conversion. Deposition of carbon and disintegration of the catalyst, especially iron catalysts, is thereby reduced. The dilute phase conversion is preferably effected in successive stages, independently controlled as to catalyst supply, density, and temperature, up to a conversion of say 50-80 per cent, the catalyst entrained in the upward flow of gas then being carried to the final dense phase from which it may be recirculated to the dilute phase stages. Preferred catalysts contain iron obtained from oxides or sulphides and promoted with alkali oxides or halides, e.g. the reduction product of Fe2O3 95.4, Al2O3 2.6 K2O 2, and SiO2 1.4 parts by weight. Dilute phase densities of 0.5-10 lb./c. ft. may be established with superficial gas velocities of 1-20 ft./sec. with particle sizes of 5-150 m , and space velocities of 2,000-20,000 v./v./hr. of fresh feed. Dense phase densities of 20-150 lb./c. ft. are obtained with gas velocities of 0.1-3 ft./sec., and space velocities of less than 5,000 v./v./hr. Classification of particles may be effected in the dense phase and those of a narrow size range circulated to the dilute phase. Temperatures may vary for example from 500-650 DEG F. in the initial zone to 550-700 DEG F. in a subsequent zone, and 600-800 DEG F. in the final dense-phase zone. Fresh feed is supplied by lines 1 and 3 to reactor 10 and iron catalyst by stand-pipe 12 from reactor 50. Conditions are controlled to give a limited turbulence and slippage of catalyst particles, sufficient to permit efficient heat transfer to the cooling surfaces 18 while permitting carry-over of catalyst to reactor 30, to which additional catalyst may be fed by stand-pipe 32, and fresh feed gas by lines 21, 23. Product gases then pass to dense phase reactor 50 provided with conventional cooling means 48. Products pass through separator 58 and separated fines are returned by pipe 60 or lines 61, 63 as desired. Clarification of particles may be effected in packing 66 and those of desired size recycled.ALSO:<PICT:0634534/IV (b)/1> The synthesis of hydrocarbons and oxygenated products from carbon monoxide and hydrogen is effected by contacting in a conversion zone with a suspension of finely divided synthesis catalyst in a gas, the concentration of catalyst in said suspension being sufficiently low to permit conversion and resultant heat release to take place at a substantially uniform rate over an extended path of contact between reactants and catalyst, unreacted gases being withdrawn and contacted with a dense turbulent fluidized catalyst mass to effect substantial completion of the conversion. Deposition of carbon and disintegration of the catalyst, especially iron catalysts, is thereby reduced. The dilute phase conversion is preferably effected in successive stages, independently controlled as to catalyst supply, density, and temperature, up to a conversion of say 50-80 per cent, the catalyst entrained in the upward flow of gas then being carried to the final dense phase from which it may be recirculated to the dilute phase stages. Preferred catalysts contain iron obtained from oxides or sulphides and promoted with alkali oxides or halides, e.g. the reduction product of Fe2O3 95.4, Al2O3 2.6, K2O, and SiO2 1.4 parts by weight. Dilute phase densities of 0.5-10 lb./c.ft. may be established with superficial gas velocities of 1-20 ft./sec. with particle sizes of 5-150m and space velocities of 2,000-20,000 v/v/hr. of fresh feed. Dense phase densities of 20-150 lb./c.ft. are obtained with gas velocities of 0.1-3 ft./sec. and space velocities of less than 5,000 v/v/hr. Classification of particles may be effected in the dense phase and those of a narrow size range circulated to the dilute phase. Temperatures may vary for example from 500-650 DEG F. in the initial zone to 550-700 DEG F. in a subsequent zone, and 600-800 DEG F. in the final dense phase zone. Fresh feed is supplied by lines 1 and 3 to reactor 10 and iron catalyst by standpipe 12 from reactor 50. Conditions are controlled to give a limited turbulence and slippage of catalyst particles, sufficient to permit efficient heat transfer to the cooling surfaces 18 while permitting carry-over of catalyst to reactor 30, to which additional catalyst may be fed by standpipe 32, and fresh feed gas by lines 21, 23. Product gases then pass to dense phase reactor 50 provided with conventional cooling means 48. Products pass through separator 58 and separated fines are returned by pipe 60 or lines 61, 63 as desired. Classification of particles may be effected in packing 66 and those of desired size recycled.